The Nip Slip aims to provide its visitors with images of hot famous girls getting their tits exposed - either willingly or by accident - so that cameras can pick up on that sweet delicious booby goodness. Note that not all of the material here is on the nip slip variety, but you will see plenty of boobs as well as a few upskirt images too! Put simply, the only thing that's required for this content to be published is for the girls starring in the material to be famous.
There are multiple daily posts with a bunch of sources used for the material. Some are amateur photographers getting good angles, others are professional photographers and paparazzi. Content from films and photo shoots also make appearances - I'd say that TheNipSlip.com is certainly more of a site devoted to celeb culture as a whole, not exclusively on the world of famous chicks getting caught out with their nipples on show. Still, it's damn good and well structured with plenty of original material, so good work guys - this place rocks.